Standard deviation is the variance in numbers. When measuring a single variable between groups one example would be the strength between men and women. Men are clearly stronger due to their biological makeup than women. The standard deviation expresses the variability of a population providing confidence in statistical conclusions (Laerd Statistics, 2004). First a standard average of strength between men and women would have to be established. When measuring strength as the single variable there would be a high standard of deviation. This would be determined through the formula square root of the variance. Through the standard of the deviation the research can show how the numbers disperse from the mean. The mean is the average number. The mean is determined by the expected standard deviation. When determining the strength of a woman compared to the strength of a man the strength of the woman would be further dispersed from the average while men would be closer to the mean.